A cell-penetrant peptide blocking C9ORF72-repeat RNA nuclear export suppresses neurodegeneration

Hexanucleotide repeat expansions in C9ORF72 are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), a spectrum of incurable debilitating neurodegenerative diseases. Here, we report a novel ALS/FTD drug concept with in vivo and in vitro therapeutic activity in preclinical models of C9ORF72-ALS/FTD. Our data demonstrate that supplementation or oral administration of a cell-penetrant peptide, which competes with the SRSF1:NXF1 interaction, confers neuroprotection by inhibiting the nuclear export of pathological C9ORF72 -repeat transcripts in various models of disease including primary neurons, patient-derived motor neurons and Drosophila . Our drug-like rationale for disrupting the nuclear export of microsatellite repeat transcripts in neurological disorders provides a promising alternative to conventional small molecule inhibitors often limited by poor blood-brain barrier penetrance. ### Competing Interest Statement GMH, MA, AJW and PJS are inventors on patents granted in the USA (US10/801027) and Europe (EP3430143) for the use of inhibitors of SRSF1 to treat neurodegenerative disorders (WO2017207979A1). The authors declare no other relationships, conditions or circumstances that present a potential conflict of interest.